Cradle for slugs cast by a vertical continuous casting operation



Dec. 3, 1963 w. HESS ETAL 3,112,537

CRADLE FOR SLUGS CAST BY Av VERTICAL CONTINUOUS CASTING OPERATION Filed 001;. 19, 1959 3 Sheets-Sheet 1 INVENTORS WALTER HESS BY RALF SCHNEIDER ATT'OR NE XS Dec. 3, 1963 w. HESS ETAL 3,112,537

CRADLE FOR SLUGS CAST BY A VERTICAL CONTINUOUS CASTING OPERATION 5 Sheets-Sheet 2 Filed Oct 19, 1959 4% R J P M m? 4 m m wma m T LF MM 7 ATTORNEYS Dec. 3, 1963 w. HESS ETAL 3,112,537

CRADLE FOR SLUGS CAST BY A VERTICAL CONTINUOUS CASTING OPERATION Filed Oct 19, 1959 3 Sheets-Sheet 3 Q 4/ 2a 4/ 3 2/ I I v Z2 25 3 26 SLIP INVENTORS WALTER HESS RALF SCHNEIDER 25 l lwiw M gg AT TORNEYS United States Patent 3,112,537 CRADLE FOR SLUGS CAST BY A VERTIUAL CONTINUOUS CASTWG OPERATION Walter Hess, Dusseldorf, and Ralf Schneider, Gelsenkirchen, Germany, assignors to Continuous Metalcast (30., Inc, Wilmington, Del., a corporation of Delaware Filed Oct. 19, 1959, Ser. No. 847,224 Claims priority, application Germany Oct. 2% 1958 7 Claims. (Cl. 2257.2)

This invention relates to slug receiving cradles, and more particularly, to a receiving cradle for slugs cast by a vertical continuous casting apparatus in which the cradle is tiltable for ejection of the slug after receipt thereof.

Vertical continuous casting apparatus, in which a material is cast in a continuous strand from which slugs are cut in lengths convenient to subsequent processing, such as rolling, are known to the art. In many applications the slug must be received, oriented, and discharged within a short time so that the receiving device can be returned to position to catch the next slug cut from the continuously moving strand.

It is, therefore, the primary object of this invention to provide a receiving cradle which will separate the slug after cutting thereof from the end of the continuous moving strand by a distance suflicient to allow orientation of the slug.

It is a further object of this invention to provide a receiving cradle to receive a slug cut from a suitable moving continuous cast strand to tilt the slug to substantially the horizontal position, eject the slug and return to the vertical position in time to receive the end of the cast strand.

It is a still further object of this invention to provide a tilting receiving cradle which will positively grasp the end of a continuous cast strand, pull the slugs cut from the strand into thecradle at a higher speed than the casting speed, tilt the slug, and eject the slug from the cradle at a still higher speed.

In accordance with these objects there is provided, in a preferred embodiment of this invention, a tiltable receiving cradle comprising rollers positioned astraddle the axis of the continuous cast strand to receive the cast strand therebetween. At least one of the rollers is driven at a speed so that the tangential velocity of the surface thereof at the point of engagement with the strand is higher than the strand movement during casting of the strand. The driven roll is rotated by a slip drive so that it is braked by engagement with the strand until the tangential velocity matches the casting velocity.

After the slug is cut from the end of the cast strand, the drive roll will accelerate to the driven speed to separate the slug from the strand by a distance suflicient to allow subsequent orientation thereof. After separation of the slug from the strand, the rolls are stopped, stopping the slug and the cradle is tilted until the slug is substan tially horizontal. The rollers are then reversed in direction to eject the slug onto roll ways for movement of the slug to subsequent machine operation. The ejection is made at a higher speed than the speed of receiving the slug. The cradle is tilted about an axis parallel to the axis of the driven roller and which may coincide with the axis of the driven roller to avoid change of the gap between the roller surfaces during tilting.

The cradle is provided with an apron to guide the received strand and to support the slug during tilting of the cradle.

A preferred embodiment of this invention is illustrated in the accompanying drawings of which:

FIGURE 1 is a vertical sectional view of a receiving cradle in accordance with the present invention;

3,112,537 Patented Dec. 3, 1Q53 FIGURE 2 is a partially sectioned view taken along lines II-II of FIGURE 1;

FIGURE 3 is a sectional view taken along lines IIIIII of FIGURE 1;

FIG. 4 is an elevation view of a portion of the apparatus shown in FIG. 1, illustrating modifications;

FIG. 5 is an elevation view of a portion of the apparatus shown in FIG. 3 in accordance with another embodiment of this invention; and

FIG. 6 is an elevation view of a portion of the apparatus shown in FIG. 3 in accordance with still another embodiment of this invention.

In FIG. 1, there is shown a continuous casting mold 104) which is cooled by water flowing through ducts 102 in the walls thereof to chill the molten metal 104 poured into the mold from a tundish 106. The mold forms a skin containing the molten metal to create a strand 3 which exits from the mold at a predetermined velocity. As the strand solidifies, it can be cut by a cutting torch 108. The torch is driven with the same transverse velocity as the strand as by piston rod operated by hydraulic cylinder 112. The strand 3 may, thus, be cut into slugs of a size suitable for subsequent processing. The strand enters a receiving cradle which accepts the slug cut from the strand and which clears the slug before the cut end of the strand reaches the cradle. In this manner, the strand may be continuously cast.

The receiving cradle, shown in different views in FIGS. 1-3, comprises rollers 1 and 2, positioned astraddle the axis of a continuous casting strand. The axis of the rollers are perpendicular to the axis of the cast strand and the rollers are positioned astraddle the strand with the separation between the surfaces matching the thickness of the strand 3. Both rollers 1 and 2 are provided with concentric cooling passages 4. In the embodiment shown, only roller 2 is driven with roller 1 being an idler roller.

The cradle frame 7 is provided with hearing 20 into which the journals 21 and 21a of the driven roll extend. The journal 21a is elongated and coupled to the shaft 2.4 of a drive motor 51 through the releasable coupling 23 and 25. The roller is water-cooled in conventional fashion through the coupling 28' and the feed pipe 26 coupled to the roller by nut 27.

The cradle frame 7 is pivotally mounted in bushings 14 for rotation about an axis concentric with the axis of the drive roller. The bushings 14 are mounted in the cover frame 12, which is connected to the main structural frame 19 through a fish plate secured to the frame 19 by bolts 17 and nuts 18. The bearings are provided with external protective shields 22. The cover frame 12 shields the roller 2 and the bearings 20 and 14 from scale flaking from the cast strand 3. The bearing cover is provided with a 'beveled edge 13 which with the beveled edge of the cradle frame provides a funnel shaped entrance to assist in centering of the cast strand 5.

In order to articulate the cradle frame about the pivot provided by hearing 14, the cradle frame is provided with trunnions 8 rotatably mounted in legs 40 integral with the cradle frame. Coupled to the trunnions is a lever 9 which, in turn, is coupled to a lever 10 by shaft 11. The lever 16 may be coupled to any suitable drive. In this manner there is provided a crank drive consisting of the linkage 9, 1t and 11 to articulate the bearing body about an axis concentric with the axis of roller 2.

The cradle frame is preferably constructed in two halves bolted together as at 30'.

The cradle is provided with an apron 5 carried by the cradle frame. The apron 5' carries bushings 36 in which the journals of the idler roller 1 are rotatably mounted. Similarly, the apron carries bushings 34 in which a guide roll 33 is rotatably mounted adjacent the entrance position of the receiving cradle. It will be noted that it is possible to provide additional idler rollers 60* FIG. 4 if guidance by such rollers is necessary. It has been found convenient to fabricate the cradle frame and apron of two parts bolted together by bolts 30 and 38, respectively.

In order to provide means for adjusting the position of roller 1 for variation in the thickness of the section of the continuous cast strand, the bearing body 7 is provided with a recess 6 into which the apron is movably inserted. The apron is movable transversely to the axis of the roller 1 to adjust the gap between roller 1 and roller 2 to the desired thickness for the application intended. This adjustment is provided by the insertion of shims 41. The roller is forced against the shim by springs 42 the tension of which may be adjusted by movement of bolts 43. In order to adjust position of the entire cradle, the cradle is movable by insertion of exchangeable wedges 44.

The adjustment of the position of both rollers 1 and 2 is necessary only when the cradle must be located with respect to the centerline of the mold. In those applications having a fixed reference edge for the whole continuous casting unit, it would, of course, be possible to locate the roller 2 on one side of the continuous casting apparatus with the associated equipment for driving the roller, and, then, merely position the roller 1 to correspond with the required strand thickness.

The apron supports the slug during tilting and is thus elongated. To supply the force to tilt the apron when the cradle frame is tilted, the cradle frame 7 is elongated on the side adjacent the roller 1 in the direction of the downwardly extending skirt on the apron and is at this point provided with an adjustable thrust bolt 45- which bears upon the surface 46 provided on the apron.

It should be noted that the apron may be provided with a catcher plate 62 (FIG. 4) suspended resiliently as by springs 64 FIG. 4 to catch the slug. As shown in FIG. 4, the catching device is preferably mounted on the lower end of the apron as by a butt plate 61.

The mode of operation is as follows:

The continuous casting strand 3 leaves the continuous casting mold and the withdrawal rolls to enter the funnelshaped opening formed by the edges 13 of the bearing cover 12 and the apron '5. The strand is gripped by the opposed roller pairs consisting of the idler roller 1 and the driven roll 2.

The driven roll is driven at a rotational rate such that the tangential velocity of the roller surface is greater than the velocity of the moving strand 3. This drive is preferably an oil-driven motor 51 fed by a constant capacity oil feed pump 52, through line 53 and return line 54. Alternatively, as illustrated in FIG. 5, the drive may comprise a motor 501 operating through a clutch 502 with a predetermined slip torque. Also, as illustrated in FIG. 6, the drive may comprise an electric motor 601 such as an induction motor wherein the slippage is taken up by the motor running characteristics. The motor 51 -may be conventional oil driven motor such as illustrated in US. Patent 2,577,242 and US. Patent 2,553,655. The pump 52 may be an identical unit to the motor and driven by a suitable source of motor power such as an electric motor 58. The motor 51 and pump 52 may be mechanically interconnected by a lever 59 so as to provide a coupling in a conventional hydraulic power transmission arrangement as set forth in the publication High Pressure Hydraulic Power Transmission by Dr. Hans Thoma, published by the Institute of Mechanical Engineers, Westminster, London, on December 13, 1957. The drive rate of such an arrangement is dependent on the angular deflection of the motor and pump from the axis of the drive shafts. However, at any fixed angular deflection, the drive rate stays constant. An over-pressure valve 55 may interconnect the delivery and return lines 53 and 5 4, respectively so as to provide a return bypass of oil delivered by pump 52 when the rollers 2 grip the cast strand allowing the motor 51 to slow down to the speed required by the casting rate of the continuous strand.

Therefore, the roller rotates at a high speed until the strand is gripped thereby. Gripping of the strand brakes the roller rotation to coincide with the speed of the continuous casting operation. Any oil over-pressure derived from the braking of the roller and the associateddrive motor can be discharged through an over-pressure valve in conventional manner.

After the slug is cut from the strand, the roller 2 will speed up under the combined influence of the drive motor and the weight of the slug falling into the cradle. Therefore, the slug is quickly separated from the end of the continuous cast strand to allow reorientation of the slug. The separation distance is adjusted to allow time to tilt the cradle, discharge the slug, and return the cradle to receive the end of the strand.

After separation of the slug from the strand, the roller 2 is stopped by brake 57 and the slug held in the cradle. At this time the crank drive will articulate the cradle frame 7, to rotate the frame and the apron into a substantially horizontal attitude. When the apron has been tilted through the requisite angle, the brake 53 is released and the direction of rotation of roller 2 is reversed by the conventional method of deflecting the motor '51 and the pump 52 via the mechanical linkage 59 to reverse the angular orientation with respect to the respective drive shafts. Thus the slug is ejected until it slides onto and over the path defined by the rollers 50. During the ejection of the slug the rotational speed of the roller 2 is maintained high to clear the cradle quickly and allow the cradle to be rapidly returned to its upright position in order to receive the moving strand from the continuouscasting device. For such purpose, it has been found advantageous to utilize an oil pump with a substantially higher delivery capacity for ejection than that used for rotation of the roller during receipt of the slug. The pump 52 ma of course, have the higher delivery capacity. However, in practice it is advantageous to provide a smaller and larger pump for the respective ejection rates along with the necessary interconnections of the plumbing. Since such interconnections do not form a significant part of the invention, they are not illustrated here.

It will be noted that it is entirely possible to use alternative drive mechanisms for tilting of the cradle in place of the crank drive illustrated. For example, a hydraulic piston 65 (FIG. 4), may be directly connected to trunnions 8.

This invention may be variously modified and embodied within the scope of the subjoined claims.

What is claimed is:

1. A cradle for a continuous casting plant having a mold to cast a continuous strand which exits from the mold at a predetermined velocity and having means for cutting said strand into slugs without interrupting the strand casting comprising a first and second roller, said first and second rollers being positioned astraddle the axis of said strand, drive means for rotating said first roller at m initial speed so that the tangential velocity of the surface thereof is higher than the transverse velocity of the strand, said drive means permit-ting the first roller to slow down so that the peripherial speed of the roller matches the strand velocity when the uncut strand enters between and is engaged by said first and second roller, said drive means driving said rollers at said initial speed when a slug is cut from said strand to draw the slug into the cradle rapidly, brake means to stop said first roller after the slug has been cut from said strand and has been received by said cradle, and means for tilting said cradle. about an axis coincident with the axis of said first roller.

2. A cradle in accordance with claim 1 which includes means for ejecting the slug from the cradle comprising means for rotating said first roller after said cradle has been tilted.

3. A cradle in accordance with claim 1 which includes means for adjusting the center line between said first and second rollers to be coincident with the axis of said strand and means for changing the distance bet-ween the axis of said first and second rollers in accordance with the thickness of the strand.

4. A cradle in accordance with claim 1 which includes an apron tiltable about an axis coincident With the axis of said first roller to guide said slab to a horizontal position.

5. A cradle in accordance with claim 4 in which said second roller -is journ-aled in said apron and which includes means for moving said apron to adjust the gap between the surface of said first and second rollers.

6. A cradle in accordance with claim 4 which includes at least one idler roller journaled in said apron.

7. A cradle in accordance with claim 1 in which said rollers are Water-cooled.

References Cited in the file of this patent UNITED STATES PATENTS 2,365,007 Rideout Dec. 12, 1944 2,599,846 Kratzenberg June 10, 1952 2,749,583 Lowenstein June 12, 1956 2,772,766 Kellam Dec. 4, 1956 2,865,516 Hedderich Dec. 23, 1958 2,931,256 Peterson Apr. 5, 1960 2,988,790 Rustemeyer June 20, 1961 

1. A CRADLE FOR A CONTINUOUS CASTING PLANT HAVING A MOLD TO CAST A CONTINUOUS STRAND WHICH EXITS FROM THE MOLD AT A PREDETERMINED VELOCITY AND HAVING MEANS FOR CUTTING SAID STRAND INTO SLUGS WITHOUT INTERRUPTING THE STRAND CASTING COMPRISING A FIRST AND SECOND ROLLER, SAID FIRST AND SECOND ROLLERS BEING POSITIONED ASTRADDLE THE AXIS OF SAID STRAND, DRIVE MEANS FOR ROTATING SAID FIRST ROLLER AT AN INITIAL SPEED SO THAT THE TANGENTIAL VELOCITY OF THE SURFACE THEREOF IS HIGHER THAN THE TRANSVERSE VELOCITY OF THE STRAND, SAID DRIVE MEANS PERMITTING THE FIRST ROLLER TO SLOW DOWN SO THAT THE PERIPHERIAL SPEED OF THE ROLLER MATCHES THE STRAND VELOCITY WHEN THE UNCUT STRAND ENTERS BETWEEN AND IS ENGAGED BY SAID FIRST AND SECOND ROLLER, SAID DRIVE MEANS DRIVING SAID ROLLERS AT SAID INITIAL SPEED WHEN A SLUG IS CUT FROM SAID STRAND TO DRAW THE SLUG INTO THE CRADLE RAPIDLY, BRAKE MEANS TO STOP SAID FIRST ROLLER AFTER THE SLUG HAS BEEN CUT FROM SAID STRAND AND HAS BEEN RECEIVED BY SAID CRADLE, AND MEANS FOR TILTING SAID CRADLE ABOUT AN AXIS COINCIDENT WITH THE AXIS OF SAID FIRST ROLLER. 